From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755686AbZAWPNc (ORCPT ); Fri, 23 Jan 2009 10:13:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752307AbZAWPNY (ORCPT ); Fri, 23 Jan 2009 10:13:24 -0500 Received: from smtp106.mail.mud.yahoo.com ([209.191.85.216]:39483 "HELO smtp106.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751185AbZAWPNX (ORCPT ); Fri, 23 Jan 2009 10:13:23 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=YwOvQpjeaoKh41EFjKbrbIh5f4bN0+hxnRvSucATCh9P99JNXEM4F8nZr1PlDIa5noI5RJ2NaE+z1LckZoElVZmknPxT13z6J1Uutk1Eu+ohn1EAhddy3+ms+mYHZ4h2zVaHYCkXcrKElOUcSqSLDPUfQfpaPqJaCOmBCO0HRb4= ; X-YMail-OSG: 0mebBZEVM1lVEFKsl6e_q2BQ9O0nqgrOfusAcPDuh6NSas562oLbrNBqsgZzes7Yr6Fog0Irg7elNZnu7WrUX.IsUFWtaYmrRrGKPUIjUpsH5YuNlWPC5jxlarWIOL2WSGnjGYb7sYNJiXDj8aICzWWRVf.6S2I_dfYobXxH4VTZW6S_bcBS.aEwvBHyQQ-- X-Yahoo-Newman-Property: ymail-3 From: Nick Piggin To: Christoph Lameter Subject: Re: [PATCH] SLUB: revert direct page allocator pass through Date: Sat, 24 Jan 2009 02:12:57 +1100 User-Agent: KMail/1.9.51 (KDE/4.0.4; ; ) Cc: Pekka J Enberg , yanmin_zhang@linux.intel.com, Andi Kleen , Matthew Wilcox , linux-kernel@vger.kernel.org, akpm@linux-foundation.org References: <200901231952.53961.nickpiggin@yahoo.com.au> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200901240212.58829.nickpiggin@yahoo.com.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Saturday 24 January 2009 02:03:22 Christoph Lameter wrote: > On Fri, 23 Jan 2009, Nick Piggin wrote: > > Hmm, it lists quite a number of advantages that I guess are being > > reverted too? What was the test case(s) that prompted this commit > > in the first place? Better ensure it doesn't slow down... > > The advantage was mainly memory savings and abilty to redefined kmallocs > to go directly to the page allocator. Totally avoids slab allocator > overhead. Well it sounds in the changelog like a massive performance advantage. Unfortunately it doesn't really say what the workload was. > I thought higher order allocations were not supposed to be used in > performance critical paths? ? You use them all the time in SLUB alone. > Didnt you want to do everything with order-0 > allocs? People don't always do what I think is best, unfortunately ;) > It seems that we currently need the slab allocators to compensate for the > performance problems in the page allocator for these higher order allocs. > I'd rather have the page allocator fixed but things are as they are. No objections from me with speeding up the page allocator of course.